In transmission systems it is common to provide the transmission with electrical connections, hydraulic connections and/or pneumatic connections for a variety of components, such as auxiliary output drives, clutches, transmission brakes, retarders, shift elements, control elements, etc.
In addition, it is know in the prior art to provide individual components of a transmission system with separate independent venting ports or devices.
A prior art method and a device, for ventilating a transmission to equalize the air pressures that are interior and exterior with respect to the transmission housing, is known from EP 0 939 250 B1, the U.S. equivalent of which is U.S. Pat. No. 6,015,444 to Craft et al. for an APPARATUS AND SYSTEM FOR VENTING A TRANSMISSION. The known transmission venting device comprises a vertically extending portion having a first end, a second end and an intermediate section extending between the first and second ends. The vertically extending portion includes an axially central passageway, that extends from the first end toward into the intermediate portion, and one or more radially extending passageways, that allow fluid communication from the central passageway to an exterior of the vertically extending portion.
The first end of the vertically extending portion has a threaded section such that the ventilation device can be screwed into the transmission. In this manner, the venting device enables ventilation from between the interior and exterior of the transmission housing. The dimensions of the axially central passage prevent a film of lubricant from forming across the central passage. The second end of the vertically extending portion has at least one flat surface enabling torque to be applied to the vertically extending portion to assist in connecting the ventilating device with the transmission housing.
The ventilation device further includes a container portion which is designed to enclose the exterior opening of the radially extending passageway within its interior. The container portion is fixed on the vertically extending portion pipe and includes at least one opening allowing airflow from the radially extending passageway to the exterior of the ventilation device. The container portion houses a filter within its interior to capture any fluid, mist and/or liquid vapour while allowing air to pass therethrough. This enables the interior of the transmission to ventilate to the outside while preventing the passage of transmission fluids therefrom.
U.S. Pat. No. 5,004,086 relates to a clutch assembly for a motor vehicle in which a complex actuating unit is provided with a common inlet(s).
Furthermore, multi-speed transmissions having transmission control elements are known in which a ventilating duct is provided in the housing (see WO 2007/031119 A1). These ducts extend from a transmission recess, formed in the transmission housing to accommodate the transmission control element, to as far as the drive output sensor. The transmission recess also serve as a space for the collection of exhaust air from a pneumatic system of the transmission.